White Sands in New Mexico during the last ice age was marshy and colder, and home to mammoths, giant sloths, as well as humans. Credit: Karen Carr

An extensive new analysis further confirms the oldest known human footprints in North America date back to the last ice age (about 23,500–21,700 years). To pinpoint their origins, researchers at the University of Arizona relied on cutting-edge methods at the United States Geological Survey (USGS) Radiocarbon Laboratory to examine hundreds of thousands of prehistoric pollen grains extracted from the tracks. According to researchers writing this week in the journal Science Advances , the team can even describe some of the dramatic environmental fluctuations experienced by these prehistoric humans within a single generation.

New Mexico’s White Sands National Park contains more than stunning vistas and desert dunes. It’s also home to one of the most controversial (and consequential) prehistoric discoveries of the last century.…